Apparatus for making dental crowns and molar projections.



B. PROSKAUER & A. IRRGANG.

APPARATUS FOR MAKING DENTAL CROWNS AND MOLAFI PROJECTIONS.

APPLICATION FILED APR- 16. I9I3.

1,143,432. Patented June 15, 191 5 IIII ,29. Pros/3am? THE NORRIS PETERS CO. PHOTO-LITHOI, WASHINGTON, D. C.

, mine snares Parana orrien BER'I'HOLD PROSKAUER, F BERLIN, AND ADOLF IRRGANG, OF BAUMSGHULENWEG,

- NEAR BERLIN, GERMANY.

Specification of Letters Patent.

Patented June 15, 1215.

Application filed April 16, 1913. Serial No. 761,567.

we To'aZZ whom it may concern ful Improved Apparatus for Making Dental Be it known that we, BERTHOLD PROSKAUER and Aoonr IRRGANG, citizens of the German Empire, and residing, respectively, at Ber-- lin and Baumschulenweg, near Berlin, Germany, have invented a certain new and use- Crowns, Molar Projections, and the like, of which the following is a specification.

Our invention relates to an apparatus for making. seamless dental-crowns, molar projections and the like, employing as the material for making-the matrix the composi tion consisting of shellac, rubber, rosin or the like. The crown casing is pressed betweenthe matrixconsisting of' the abovenamed material and a counter-die held by the aid of a stem in the punch.

Our invention is illustrated in the accompanying drawing, wherein Figures 1 to 3 illustrate a mold which serves for producing a counter-die provided with a stem, Fig. 1 being a top plan view of the lower box, Fig. 2 a bottom plan view of the upper box,andFig. 3 a longitudinal section through the closedbox' taken on the line AB; Figs. 4: to 8 show a stamping apparatus, Fig. 4 being a-longitudinal section taken on the line IK in Fig. 6, Fig. 5 a longitudinal section takenon the line L.M in Fig. 6, and Figs. 6, 7 and 8 cross-sections taken on the lines N-O, PQ, and RS, respectively, in Fig. 1; Figs. 9 and 10 show a device for subsequently stamping the contours, andare a longitudinal section, and a cross-section taken on the line TU in Fig. 4:, respectively.

Referring to the drawing, 1 indicates the .frameof the lower molding box which is provided with a hollow portion 2 and an edge portion 3. In the latter is a conical recess '4: having therein a groove 5 terminating in a point. By-means of dowel pins 6 the upper box 8 having the hole 7 can be applied to the lower box, the said upper box corresponding in its external form with the lower box 1 except that it lacks the groove 5. Intothe conical recess 4 of the upper and lower boxes fits a stopper 9 which is preferably provided with a grip 10. The upper and lower boxes may be held together by means of springsinstead of by the pins 6.

The counter-die located in the molding box and formed in the manner hereinafter described comprises the stem 4 having the r the lug 5 and fitting in a punch 11, the upper end of which is tapered and provided with a head 12. Inthe middle of the punch 11 1s a bore 13, which terminates in a chamber 14. The punch has at its outer periphery a groove 15 for-the reception of a guide (see Fig.

he matrix is formed in a cup-like mem- I ber 16 illustrated in Figs. 4, 5 and 8. The

said member preferably consists of a cylin der whose lower end 17 has an aperture 18, and in which a plate 19 can be fitted. In the inside of the stamping member 16 knives can be arranged to which recesses in the extension of the punch 11 must then correspond. Moreover, a setting groove 20 is provided in the chamber 1 1 of the punch 11 and a guiding groove 21 on the outside of the stampingmember 16, the latter groove corresponding to the guiding groove 15 of the punch 11. The lower end 22 of the punch 11 has an external thread, on which a projection 23 having an internal thread can be screwed. The latter is turned at its lower end to form a conical portion 24: and runs out into an annular lip or cutting edge 25. r

The crown casings and the like are stamped in a cylinder 26 which is. suitably roughened on its outer surface or so formed that it can be readily held by the hand. At about two-thirds of itsheight the cylinder 26 is provided with two opposite holes 27, 28, through which a pin can be inserted for purpose of securing the punch 16 so that it projects out of the cylinder 26. In this position the matrix material is inserted, whereupon after the pin has been withdrawn from the holes 27, 28, the punch is lowered intothe position shown in Fig. 4.

The cup-like member 29 illustrated in Figs. 9 and 10 for the subsequent stamping of contours will now be described. This member has an aperture 30, and a setting lug 81, and is tapered in its central portion for the purpose of receiving the material serving as the mold, leadbeing preferably employed.

By means of the described devices the process of making the crowns, etc., can be carried out as follows: The counter-die is first of all provided with anormal stem, independently of its special shape. This is effected by the gypsumreplica of the tooth to beprovided with a crown and produced in known manner being first of all repro duced in gypsum in the lower box 1 and in the upper box 8, the stopper 9 being in- After the removal of the stopper manner has the stem I seen in Fig. 9 with the lug 5, which fits in a corresponding groove 20 of the punch 11. In order to make the matrix the stamping piece 16 is filled in the above described manner with the molding material of the character mentioned, whereupon it is out into its position at the lower end of the stamping cylinder 26. I-Iereupon the punch 11, carrying at its lower end the counter-die a, is introduced and moved downward so far that the matrix is produced in the still soft molding material. The position which the matrix and counterdie take up relative to one another isinsured during the entire subsequent operation by means of the guiding grooves in the stamping piece 16 and punch 11 and by the guiding lugs on the stamping cylinder 26., In consequence of this, after the cooling and accompanying hardening of the molding material the counter-die and matrix can be removed without hesitation from the stamping cylinder in order to separatethem, it being noted that in the case of smooth teeth such separation is effected simply by withdrawing the punch 11, whereas in the case of teeth having overhanging portions the matrix must first be detached. After the cas-. ing serving for the production of the dental crown has been lightly struck on the counterdie and cut to the length of tooth, the punch 11 having the projection 23 is inserted into the stamping cylinder 26 and driven down, the crown being thus formed between the matrix and the counter-die. The employed molding material consisting of shellac, rosin, rubber and'the like after having cooled becomes sufliciently hard and firm, to press the gold casing between itself and the c0unterdie without folds, also it has the property of yielding sufficiently under pressure to allow the formation of an intermediate space which sutiices to permit the counter-die provided with a gold casing to be again inserted, the pressure exerted by the said projection on the matrix material presses the latter together around the casing for the crown both uniformly and from all sides. The punch is preferably driven down by blows of a hammer but it will be understood, however, that the crowns can be pressed mechanically by means of the mechanically and hydraulically driven presses well known in dentistry. Finally it may be stated that possible unevennesses which might be ob served with teeth having molar projections Copies ot this patent may be obtainedgfor 'ing, an internally conical member moun stood that the position of its contours which have been struck before the crownicasing 1s inserted 1n the lead block 32 'is' secured 'owing to the setting lugs 31'.

The apparatus according to our invention can of course be employednot only for manufacturing dental crowns and the like but also for all other small stamping work car j f ried out in dentistry, without regard to the material to be employed. Y We claim: i a

1. In a device of the character described, the combination with a casing adapted to contain a matrix at one end thereof, of a plunger adapted to reciprocate in the easing and havingtherein a conically hollowed annular projection for uniformly compressing the matrix on all sides when the plunger is driven into the casing, the end of the plunger'in the casing having a recess for receiving a counteredie, i

2. Ina device of the character described, the combination with a casing adapted to containa matrix at one end thereof, ofa plunger adapted to reciprocate in the casing and having therein conically hollowed annular projection for uniformly compressing thegmatrix on all sides when the plunger is driven into the casing, the end of the plunger in the'casing having a longitudinally groovedrecess for receivlng a counter-die,

In a device of the character described, 7

the combination of an outer casing, a matrix casing normally at one end thereof, a plunadapted to reciprocate 1n the outer casand on the-plunger and adapted to enter into 1 the matrix casing, wherebyiwhen the plun ger is pressed inward, said member will compress a matrix in-the'matrix casing.

t. In a device of the character described, the combination of an outer casing, a matrix casing normally-at one end thereof, a, plunger adapted to reciprocate in the outer casing, an internally conicalymember mounted on the plunger and ;.adapted to enter into the matrix casing, the outer casing having two transverse holes inthe wall thereof at such a distance from the other end that said member can beheld projecting out of the outer casing by: a pin inserted into said holes, for the purpose specified.

In testimony whereof, we afiix our signatures in the presence of two witnesses.

BERTHOLD PEOSKAUER. AD OLF' IRRGANG;

Witnesses:

WOLDEMAR I'IAUPT, HENRY Hasrnn.

five cents each, by addressing the Commissioner of Patents,

Washington, D. 0; 

